Tail rotor pitch in a helicopter is controlled in response to commands from the pilot in order to control the helicopter. These commands are provided to place the aircraft in a coordinated turn when the pilot commands a banked turn, or can also be used to command a flat turn (i.e., no bank). These commands by the pilot are input to a flight control system which computes the appropriate command for the control of tail rotor pitch.
In an attack helicopter the responsive of the helicopter about its yaw axis is crucial in combat situations. The aircraft must be capable of quickly moving about its yaw axis to bring its weapons to bear on a target. Therefore the flight control system has to be capable of responding with a tail rotor command which provides such responsive when a yaw input is received from the pilot. The tail rotor command must be predictable and repeatable in response to similar pilot inputs at high airspeeds, leading to a more capable attack helicopter.